115 lines
4 KiB
C++
115 lines
4 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* Based on LLVM/Clang.
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*
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* This file is distributed under the University of Illinois Open Source
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* License. See LICENSE.TXT for details.
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*
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*/
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#include <config_global.h>
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// If there is support for warn_unused attribute even in STL classes, then there's
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// no point in having this check enabled, otherwise keep it at least for STL
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// (LO classes won't get duplicated warnings, as the attribute is different).
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#if !HAVE_GCC_ATTRIBUTE_WARN_UNUSED_STL
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#include "unusedvariablecheck.hxx"
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#include <clang/AST/Attr.h>
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namespace loplugin
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{
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/*
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This is a compile check.
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Check for unused classes where the compiler cannot decide (e.g. because of
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non-trivial or extern ctors) if a variable is unused if only its ctor/dtor
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are called and nothing else. For example std::vector is a class where
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the ctor may call further functions, but an unused std::string variable
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does nothing. On the other hand, std::lock_guard instances are used
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for their dtors and so are not unused even if not otherwise accessed.
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Classes which are safe to be warned about need to be marked using
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SAL_WARN_UNUSED (see e.g. OUString). For external classes such as std::vector
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that cannot be edited there is a manual list below.
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*/
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UnusedVariableCheck::UnusedVariableCheck( const InstantiationData& data )
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: Plugin( data )
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{
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}
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void UnusedVariableCheck::run()
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{
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TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
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}
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bool UnusedVariableCheck::VisitVarDecl( const VarDecl* var )
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{
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if( ignoreLocation( var ))
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return true;
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if( var->isReferenced() || var->isUsed())
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return true;
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if( var->isDefinedOutsideFunctionOrMethod())
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return true;
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if( CXXRecordDecl* type = var->getType()->getAsCXXRecordDecl())
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{
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bool warn_unused = false;
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if( type->hasAttrs())
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{
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// Clang currently has no support for custom attributes, but
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// the annotate attribute comes close, so check for __attribute__((annotate("lo_warn_unused")))
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for( specific_attr_iterator<AnnotateAttr> i = type->specific_attr_begin<AnnotateAttr>(),
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e = type->specific_attr_end<AnnotateAttr>();
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i != e;
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++i )
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{
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if( (*i)->getAnnotation() == "lo_warn_unused" )
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{
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warn_unused = true;
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break;
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}
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}
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}
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if( !warn_unused )
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{
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string n = type->getQualifiedNameAsString();
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// Check some common non-LO types.
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if( n == "std::string" || n == "std::basic_string"
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|| n == "std::list" || n == "std::__debug::list"
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|| n == "std::vector" || n == "std::__debug::vector" )
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warn_unused = true;
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}
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if( warn_unused )
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{
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if( const ParmVarDecl* param = dyn_cast< ParmVarDecl >( var ))
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{
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if( !param->getDeclName())
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return true; // unnamed parameter -> unused
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// If this declaration does not have a body, then the parameter is indeed not used,
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// so ignore.
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if( const FunctionDecl* func = dyn_cast_or_null< FunctionDecl >( param->getParentFunctionOrMethod()))
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if( !func->doesThisDeclarationHaveABody())
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return true;
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report( DiagnosticsEngine::Warning, "unused parameter %0",
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var->getLocation()) << var->getDeclName();
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}
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else
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report( DiagnosticsEngine::Warning, "unused variable %0",
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var->getLocation()) << var->getDeclName();
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}
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}
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return true;
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}
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static Plugin::Registration< UnusedVariableCheck > X( "unusedvariablecheck" );
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} // namespace
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#endif
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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